News of the switch was made during the Select Board meeting Wednesday by Town Manager John Haverstock during his biweekly report to the board.

Jim Stewart, manager of Omya’s Florence plant, said Carter was offered the opportunity to switch his tractor fleet to LNG but declined.

Stewart said the transition to Casella will take place in the fall. He said Omya’s contract with Carter ends Dec. 31.

Casella Construction has been in the aggregate transportation business for 20 years and the Omya contract is a natural extension of the business, said John Casella II, operations group manager for Casella Construction, who responded via email to a series of questions.

“When this opportunity presented itself, we felt it would give us the opportunity to help minimize the cyclical nature of our business and bring a more consistent workload,” Casella said.

Casella will purchase 14 Kenworth T-800 tractors powered by Cummins natural gas engines. The company will also purchase 14 dump trailers to haul the marble ore from Middlebury to the calcium carbonate plant in the Florence section of Pittsford.

Stewart said each dump trailer holds approximately 30 tons of marble ore.

Casella declined to disclose how much the company is paying for its LNG tractor truck fleet.

“Our team spent many hours working to ensure that our tractor trailer specifications are best in this application to safely and efficiently perform the contract,” Casella said. “Notwithstanding the contemporary specifications on these new trucks, they will look and function similar to the trucks currently hauling.”

Omya will supply fuel for Casella’s trucks at its LNG facility. Omya invested $10 million to build its LNG depot, switching from more expensive fuel oil to run the plant’s dryers.

Having Casella haul for the company with LNG trucks will also save Omya money on its fuel bill.

“Part of our contract with Carter, we were paying for the fuel to haul,” Stewart said.

Omya will also supply fuel for Casella’s trucks, but LNG will save at least 25 percent compared to fueling Carter’s diesel trucks, he said.

“The other reason is it’s a cleaner burn, it’s better for the environment and all those good things by burning natural gas instead of diesel on the trucks,” Stewart said.

Casella said both companies have a similar business philosophy on sustainability and the environment.

“We feel natural gas, in many applications, is the future of a more vibrant business model,” he said. “I say this not only from a financial perspective but from a common sense perspective. It just makes sense.”

He said the company is committed to hiring Carter and Dido “drivers who would like to stay on the route as long as they meet our driver safety standards.”